Equalizer coefficient determination in the frequency domain for MIMO/MISO radio

ABSTRACT

A Radio Frequency (RF) receiver includes a RF front end and a baseband processing module coupled to the RF front end that is operable to receive a time domain signal that includes multiple information signals, each having training symbols and time domain data symbols. The baseband processing module includes a channel estimator that processes the training symbols to produce respective time domain channel estimates, a Fast Fourier Transformer converts the time domain channel estimates to the frequency domain to produce frequency domain channel estimates, a weight calculator operable to produce frequency domain equalizer coefficients based upon the frequency domain channel estimates, an Inverse Fast Fourier Transformer operable to convert the frequency domain equalizer coefficients to the time domain to produce time domain equalizer coefficients, and an equalizer operable to equalize the time domain data symbols using the time domain equalizer coefficients. The RF receiver supports STTD, MISO, and MIMO operations.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a continuation-in-part of:

Utility application Ser. No. 11/524,584 filed on Sep. 21, 2006, andentitled “FREQUENCY DOMAIN EQUALIZER FOR DUAL ANTENNA RADIO,” (BP5477),and

Utility application Ser. No. 11/524,580 filed on Sep. 21, 2006, andentitled “FREQUENCY DOMAIN EQUALIZER WITH ONE DOMINATE INTERFERENCECANCELLATION FOR DUAL ANTENNA RADIO,” (BP5595), both of which areincorporated herein in their entirety by reference for all purposes.

BACKGROUND

1. Technical Field

The present invention relates generally to wireless communicationsystems; and more particularly to the equalization of datacommunications by a wireless radio in a wireless communication system.

2. Related Art

Cellular wireless communication systems support wireless communicationservices in many populated areas of the world. Cellular wirelesscommunication systems include a “network infrastructure” that wirelesslycommunicates with wireless terminals within a respective servicecoverage area. The network infrastructure typically includes a pluralityof base stations dispersed throughout the service coverage area, each ofwhich supports wireless communications within a respective cell (or setof sectors). The base stations couple to base station controllers(BSCs), with each BSC serving a plurality of base stations. Each BSCcouples to a mobile switching center (MSC). Each BSC also typicallydirectly or indirectly couples to the Internet.

In operation, each base station communicates with a plurality ofwireless terminals operating in its serviced cell/sectors. A BSC coupledto the base station routes voice communications between the MSC and theserving base station. The MSC routes the voice communication to anotherMSC or to the PSTN. BSCs route data communications between a servicingbase station and a packet data network that may include or couple to theInternet. Transmissions from base stations to wireless terminals arereferred to as “forward link” transmissions while transmissions fromwireless terminals to base stations are referred to as “reverse link”transmissions. The volume of data transmitted on the forward linktypically exceeds the volume of data transmitted on the reverse link.Such is the case because data users typically issue commands to requestdata from data sources, e.g., web servers, and the web servers providethe data to the wireless terminals.

Wireless links between base stations and their serviced wirelessterminals typically operate according to one (or more) of a plurality ofoperating standards. These operating standards define the manner inwhich the wireless link may be allocated, setup, serviced, and torndown. Popular currently employed cellular standards include the GlobalSystem for Mobile telecommunications (GSM) standards, the North AmericanCode Division Multiple Access (CDMA) standards, and the North AmericanTime Division Multiple Access (TDMA) standards, among others. Theseoperating standards support both voice communications and datacommunications. More recently introduced operating standards include theUniversal Mobile Telecommunications Services (UMTS)/Wideband CDMA(WCDMA) standards. The UMTS/WCDMA standards employ CDMA principles andsupport high throughput, both voice and data.

The wireless link between a base station and a serviced wirelessterminal is referred to as a “channel.” The channel distorts and addsnoise to wireless transmissions serviced by the channel. “Channelequalization” is a process employed by a wireless receiver, e.g.,wireless terminal, in an attempt to obviate the effects of the channel.While channel equalization is certainly helpful in obviating the effectsof the channel, the characteristics of the channel are constantlychanging. Thus, coefficients of a channel equalizer must be continuallyupdated. However, generating coefficients of the channel equalizer is adifficult and time consuming process. Thus, a need exists for animproved methodology for determining equalizer coefficients.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to apparatus and methods of operationthat are further described in the following Brief Description of theDrawings, the Detailed Description of the Invention, and the claims.Other features and advantages of the present invention will becomeapparent from the following detailed description of the invention madewith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system diagram illustrating a portion of a cellular wirelesscommunication system that supports wireless terminals operatingaccording to the present invention;

FIG. 2 is a block diagram functionally illustrating a wireless terminalconstructed according to the present invention;

FIG. 3 is a block diagram illustrating a multiple Radio Frequency (RF)front end (receiver/transmitter) radio constructed according to anembodiment of the present invention;

FIG. 4 is a block diagram illustrating components of a basebandprocessing module according to embodiments of the present invention;

FIG. 5 is a block diagram illustrating equalization components of abaseband processing module according to a first embodiment of thepresent invention;

FIG. 6 is a block diagram illustrating equalization components of abaseband processing module according to a first embodiment of thepresent invention;

FIG. 7 is a flow chart illustrating equalization operations according toan embodiment of the present invention;

FIG. 8 is a flow chart illustrating equalization operations according toan embodiment of the present invention;

FIG. 9A is a block diagram illustrating a Multiple-Input-Single-Output(MISO) transmission system supported by equalization operationembodiments of the present invention operate;

FIG. 9B is a block diagram illustrating a Multiple-Input-Multiple-Output(MIMO) transmission system supported by equalization operationembodiments of the present invention operate;

FIG. 10 is a block diagram illustrating equalization components of abaseband processing module according to a third embodiment of thepresent invention;

FIG. 11 is a flow chart illustrating equalization operations accordingto the third embodiment of the present invention;

FIG. 12 is a block diagram illustrating equalization components of abaseband processing module according to a fourth embodiment of thepresent invention; and

FIG. 13 is a flow chart illustrating equalization operations accordingto the fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system diagram illustrating a portion of a cellular wirelesscommunication system 100 that supports wireless terminals operatingaccording to the present invention. The cellular wireless communicationsystem 100 includes a Public Switched Telephone Network (PSTN) Interface101, e.g., Mobile Switching Center, a wireless network packet datanetwork 102 that includes GPRS Support Nodes, EDGE Support Nodes, WCDMASupport Nodes, and other components, Radio Network Controllers/BaseStation Controllers (RNC/BSCs) 152 and 154, and base stations/node Bs103, 104, 105, and 106. The wireless network packet data network 102couples to additional private and public packet data networks 114. e.g.,the Internet, WANs, LANs, etc. A conventional voice terminal 121 couplesto the PSTN 110. A Voice over Internet Protocol (VoIP) terminal 123 anda personal computer 125 couple to the Internet/WAN 114. The PSTNInterface 101 couples to the PSTN 110. Of course, this particularstructure may vary from system to system.

Each of the base stations/node Bs 103-106 services a cell/set of sectorswithin which it supports wireless communications. Wireless links thatinclude both forward link components and reverse link components supportwireless communications between the base stations and their servicedwireless terminals. These wireless links support digital datacommunications, VoIP communications, and digital multimediacommunications. The cellular wireless communication system 100 may alsobe backward compatible in supporting analog operations as well. Thecellular wireless communication system 100 supports one or more of theUMTS/WCDMA standards, the Global System for Mobile telecommunications(GSM) standards, the GSM General Packet Radio Service (GPRS) extensionto GSM, the Enhanced Data rates for GSM (or Global) Evolution (EDGE)standards, one or more Wideband Code Division Multiple Access (WCDMA)standards, and/or various other CDMA standards, TDMA standards and/orFDMA standards, etc.

Wireless terminals 116, 118, 120, 122, 124, 126, 128, and 130 couple tothe cellular wireless communication system 100 via wireless links withthe base stations/node Bs 103-106. As illustrated, wireless terminalsmay include cellular telephones 116 and 118, laptop computers 120 and122, desktop computers 124 and 126, and data terminals 128 and 130.However, the cellular wireless communication system 100 supportscommunications with other types of wireless terminals as well. As isgenerally known, devices such as laptop computers 120 and 122, desktopcomputers 124 and 126, data terminals 128 and 130, and cellulartelephones 116 and 118, are enabled to “surf” the Internet (packet datanetwork) 114, transmit and receive data communications such as email,transmit and receive files, and to perform other data operations. Manyof these data operations have significant download data-raterequirements while the upload data-rate requirements are not as severe.Some or all of the wireless terminals 116-130 are therefore enabled tosupport the EDGE operating standard, the GPRS standard, the UMTS/WCDMAstandards, the HSDPA standards, the WCDMA standards, and/or the GSMstandards. Further, some or all of the wireless terminals 116-130 areenabled to perform equalization operations of the present invention tosupport these high speed data operating standards.

FIG. 2 is a block diagram functionally illustrating a wireless terminalconstructed according to the present invention. The wireless terminalincludes host processing components 202 and an associated radio 204. Forcellular telephones, the host processing components and the radio 204are contained within a single housing. In some cellular telephones, thehost processing components 202 and some or all of the components of theradio 204 are formed on a single Integrated Circuit (IC). For personaldigital assistants hosts, laptop hosts, and/or personal computer hosts,the radio 204 may reside within an expansion card or upon a mother boardand, therefore, be housed separately from the host processing components202. The host processing components 202 include at least a processingmodule 206, memory 208, radio interface 210, an input interface 212, andan output interface 214. The processing module 206 and memory 208execute instructions to support host terminal functions. For example,for a cellular telephone host device, the processing module 206 performsuser interface operations and executes host software programs amongother operations.

The radio interface 210 allows data to be received from and sent to theradio 204. For data received from the radio 204 (e.g., inbound data),the radio interface 210 provides the data to the processing module 206for further processing and/or routing to the output interface 214. Theoutput interface 214 provides connectivity to an output display devicesuch as a display, monitor, speakers, et cetera such that the receiveddata may be displayed. The radio interface 210 also provides data fromthe processing module 206 to the radio 204. The processing module 206may receive the outbound data from an input device such as a keyboard,keypad, microphone, et cetera via the input interface 212 or generatethe data itself. For data received via the input interface 212, theprocessing module 206 may perform a corresponding host function on thedata and/or route it to the radio 204 via the radio interface 210.

Radio 204 includes a host interface 220, baseband processing module 222(baseband processor) 222, analog-to-digital converter 224,filtering/gain module 226, down conversion module 228, low noiseamplifier 230, local oscillation module 232, memory 234,digital-to-analog converter 236, filtering/gain module 238,up-conversion module 240, power amplifier 242, RX filter module 264, TXfilter module 258, TX/RX switch module 260, and antenna 248. Antenna 248may be a single antenna that is shared by transmit and receive paths(half-duplex) or may include separate antennas for the transmit path andreceive path (full-duplex). The antenna implementation will depend onthe particular standard to which the wireless communication device iscompliant.

The baseband processing module 222 in combination with operationalinstructions stored in memory 234, execute digital receiver functionsand digital transmitter functions. The digital receiver functionsinclude, but are not limited to, digital intermediate frequency tobaseband conversion, demodulation, constellation demapping,descrambling, and/or decoding. The digital transmitter functionsinclude, but are not limited to, encoding, scrambling, constellationmapping, modulation, and/or digital baseband to IF conversion. Thetransmit and receive functions provided by the baseband processingmodule 222 may be implemented using shared processing devices and/orindividual processing devices. Processing devices may includemicroprocessors, micro-controllers, digital signal processors,microcomputers, central processing units, field programmable gatearrays, programmable logic devices, state machines, logic circuitry,analog circuitry, digital circuitry, and/or any device that manipulatessignals (analog and/or digital) based on operational instructions. Thememory 234 may be a single memory device or a plurality of memorydevices. Such a memory device may be a read-only memory, random accessmemory, volatile memory, non-volatile memory, static memory, dynamicmemory, flash memory, and/or any device that stores digital information.Note that when the baseband processing module 222 implements one or moreof its functions via a state machine, analog circuitry, digitalcircuitry, and/or logic circuitry, the memory storing the correspondingoperational instructions is embedded with the circuitry comprising thestate machine, analog circuitry, digital circuitry, and/or logiccircuitry.

In operation, the radio 204 receives outbound data 250 from the hostprocessing components via the host interface 220. The host interface 220routes the outbound data 250 to the baseband processing module 222,which processes the outbound data 250 in accordance with a particularwireless communication standard (e.g., UMTS/WCDMA, GSM, GPRS, EDGE, etcetera) to produce digital transmission formatted data 252. The digitaltransmission formatted data 252 is a digital base-band signal or adigital low IF signal, where the low IF will be in the frequency rangeof zero to a few kilohertz/megahertz.

The digital-to-analog converter 236 converts the digital transmissionformatted data 252 from the digital domain to the analog domain. Thefiltering/gain module 238 filters and/or adjusts the gain of the analogsignal prior to providing it to the up-conversion module 240. Theup-conversion module 240 directly converts the analog baseband or low IFsignal into an RF signal based on a transmitter local oscillation 254provided by local oscillation module 232. The power amplifier 242amplifies the RF signal to produce outbound RF signal 256, which isfiltered by the TX filter module 258. The TX/RX switch module 260receives the amplified and filtered RF signal from the TX filter module258 and provides the output RF signal 256 signal to the antenna 248,which transmits the outbound RF signal 256 to a targeted device such asa base station 103-106.

The radio 204 also receives an inbound RF signal 262, which wastransmitted by a base station via the antenna 248, the TX/RX switchmodule 260, and the RX filter module 264. The low noise amplifier 230receives inbound RF signal 262 and amplifies the inbound RF signal 262to produce an amplified inbound RF signal. The low noise amplifier 230provides the amplified inbound RF signal to the down conversion module228, which converts the amplified inbound RF signal into an inbound lowIF signal or baseband signal based on a receiver local oscillation 266provided by local oscillation module 232. The down conversion module 228provides the inbound low IF signal (or baseband signal) to thefiltering/gain module 226, which filters and/or adjusts the gain of thesignal before providing it to the analog to digital converter 224. Theanalog-to-digital converter 224 converts the filtered inbound low IFsignal (or baseband signal) from the analog domain to the digital domainto produce digital reception formatted data 268. The baseband processingmodule 222 demodulates, demaps, descrambles, and/or decodes the digitalreception formatted data 268 to recapture inbound data 270 in accordancewith the particular wireless communication standard being implemented byradio 204. The host interface 220 provides the recaptured inbound data270 to the host processing components 202 via the radio interface 210.

As the reader will appreciate, all components of the radio 204,including the baseband processing module 222 and the RF front endcomponents may be formed on a single integrated circuit. In anotherconstruct, the baseband processing module 222 and the RF front endcomponents of the radio 204 may be formed on separate integratedcircuits. The radio 204 may be formed on a single integrated circuitalong with the host processing components 202. In still otherembodiments, the baseband processing module 222 and the host processingcomponents 202 may be formed on separate integrated circuits. Thus, allcomponents of FIG. 2 excluding the antenna, display, speakers, et ceteraand keyboard, keypad, microphone, et cetera may be formed on a singleintegrated circuit. Many differing constructs integrated circuitconstructs are possible without departing from the teachings of thepresent invention. According to the present invention, the basebandprocessing module 222 equalizes the digital transmission formatted data(baseband TX signal) 252 in a novel manner. Various techniques forperforming these equalization operations will be described furtherherein with reference to FIGS. 3-13.

FIG. 3 is a block diagram illustrating a multiple Radio Frequency (RF)front end (receiver/transmitter) radio 300 constructed according to anembodiment of the present invention. The radio 300 includes a basebandprocessing module 222 and a plurality of RF front ends, including RFfront end 1 302, RF front end 2 304, RF front end 3 306, and RF frontend N 308. These RF front ends 302, 304, 306, and 308 are serviced byantennas 310, 312, 318, and 316, respectively. The radio 300 may servicea plurality of diversity paths of a single transmitted signal. Thus, inone simple embodiment of a diversity path implementation, the radio 300includes a first RF front end 302, a second RF front end 304, and thebaseband processing module 222. This embodiment will be describedfurther with reference to FIG. 5. Alternately, the plurality of RF frontends 302-308 may service Multiple Input Multiple Output (MIMO)communications, each RF front end 302-308 assigned a respective MIMOdata path. MIMO communications are currently implemented in WLANimplementations such as IEEE 802.11n. In either case, the principles ofthe present invention may be applied to a radio 300 having two or moreRF front ends.

FIG. 4 is a block diagram illustrating components of a basebandprocessing module 222 according to an embodiment of the presentinvention. The baseband processing module (baseband processor) 222includes a processor 402, a memory interface 404, onboard memory 406, adownlink/uplink interface 408, TX processing components 410, and a TXinterface 412. The baseband processing module 222 further includes an RXinterface 414, a cell searcher module 416, a multi-path scanner module418, a rake receiver combiner 420, and a turbo decoding module 422. Thebaseband processing module 222 couples in some embodiments to externalmemory 234. However, in other embodiments, memory 406 fulfills thememory requirements of the baseband processing module 402.

As was previously described with reference to FIG. 2, the basebandprocessing module receives outbound data 250 from coupled hostprocessing components 202 and provides inbound data 270 to the coupledhost processing components 202. Further, the baseband processing module222 provides digital formatted transmission data (baseband TX signal)252 to a coupled RF front end. The baseband processing module 222receives digital reception formatted data (baseband RX signal) 268 fromthe coupled RF front end. As was previously described with reference toFIG. 2, an ADC 222 produces the digital reception formatted data(baseband RX data) 268 while the DAC 236 of the RF front end receivesthe digital transmission formatted data (baseband TX signal) 252 fromthe baseband processing module 222.

According to the particular embodiment of the present inventionillustrated in FIG. 4, the downlink/uplink interface 408 is operable toreceive the outbound data 250 from coupled host processing components,e.g., the host processing component 202 via host interface 220. Further,the downlink/uplink interface 408 is operable to provide inbound data270 to the coupled host processing components 202 via the host interface220. TX processing component 410 and TX interface 412 communicativelycouple to the RF front end as illustrated in FIG. 2 and to thedownlink/uplink interface 408. The TX processing components 410 and TXinterface 412 are operable to receive the outbound data from thedownlink/uplink interface 404, to process the outbound data to producethe baseband TX signal 252 and to output the baseband TX signal 252 tothe RF front end as was described with reference to FIG. 2. RXprocessing components including the RX interface 414, rake receivercombiner 420 and in some cases the processor 402 are operable to receivethe RX baseband signal 268 from the RF front end.

Equalization processing operations implemented in an RF receiveraccording to the present invention may be implemented by one or more ofthe components of the baseband processing module 222. In a firstconstruct, the equalization operations are implemented as equalizationoperations 415 a by processor 402. The equalization operations 415 a maybe implemented in software, hardware, or a combination of software andhardware. When the equalization operations 415 a are implemented bysoftware instructions, the processor 402 retrieves instructions viamemory interface 404 and executes such software instructions toimplement the equalization operations 415 a.

In another construct, a dedicated equalization block 415 b residesbetween the RX interface 414 and modules 416, 418, and 420 and performsthe equalization operations of the present invention. With thisconstruct, the equalization operations 415 b may be implemented viahardware, software, or a combination of hardware and software. Inanother construct of the equalization operations according to thepresent invention, the equalization operations 415 c are performedwithin rake receiver combiner module 420 by equalization operations 415c. The equalization operations 415 c may be implemented via hardware,software, or a combination of these to execute the equalizationoperations of the present invention.

As is further shown in FIG. 4, the digital reception formatted data 268may include a plurality of signal paths. Each one of these signal pathsmay be received from a respective RF front end such as was illustratedin FIG. 3 and described there with. Thus, each of the digital receptionformatted data versions 268 may be a different multi-path version of asingle received signal or different RF signal such as in a MIMO system.

FIG. 5 is a block diagram illustrating equalization components of abaseband processing module according to a first embodiment of thepresent invention. These components of the baseband processing module222 perform equalization operations according to the present invention.Of course, a baseband processing module 222 would include additionalcomponents in addition to as those illustrated in FIG. 5. The functionalblocks of FIG. 5 may be implemented in dedicated hardware, generalpurpose hardware, software, or a combination of dedicated hardware,general purpose hardware, and software.

The components of the baseband processing module 222 of FIG. 5 includefirst diversity path components, second diversity path components, andshared components. As was described with reference to FIG. 3, an RFtransceiver (transmitter/receiver), may include a plurality of receivesignal paths. The plurality of receive signal paths may includecomponents that operate upon different multi-path versions of a singletransmitted signal or upon signals that include different data.According to the embodiment of FIG. 5, the functional components operateupon different multi-path versions of a single RF transmitted timedomain signal.

The first diversity path component includes a cluster pathprocessor/channel estimation block 504, a Fast Fourier Transform (FFT)block 506, multiplier 512, Inverse Fast Fourier Transform (IFFT) block514, tap ordering block 516, and time domain equalizer 518. The seconddiversity path components include cluster path processing/channelestimation block 524, FFT block 526, multiplier 530, IFFT block 532, tapordering block 534, and time domain equalizer 536. The shared processingblocks of the RF receiver of FIG. 5 include a Minimum Mean Square Error(MMSE) weight calculation block 510, a noise variance estimation block502, and a combiner 538.

In its operations, the first diversity path operates upon a first timedomain signal 502. The first time domain signal 502 includes first timedomain training symbols and first time domain data symbols. As isgenerally known, frames of transmitted symbols in an RF system typicallyinclude a preamble that has training symbols and a payload portion thatcarries data symbols. The training symbols are used by channelestimation operations to produce equalizer coefficients that are thenused for equalization of the data symbols. The CPP/channel estimationblock 504 is operable to process the first time domain training symbolsof the first time domain signal 502 to produce a first time domainchannel estimate 508. The FFT block 506 is operable to invert the firsttime domain channel estimate to the frequency domain to produce a firstfrequency domain channel estimate 508.

Likewise, the second diversity path is operable to receive a second timedomain signal 522 that includes second time domain training symbols andsecond time domain data symbols. The CPP/channel estimation block 524 isoperable to process the second time domain training symbols to produce asecond time domain channel estimate. The FFT block 526 is operable toconvert the second time domain channel estimate to the frequency domainto produce a second frequency domain channel estimate 528.

The MMSE/weight calculation block 510 is operable to receive noisevariance estimation parameters from noise variance estimation block 502and to produce first frequency domain equalizer coefficients 511 andsecond frequency domain equalizer coefficients 513 based upon the firstfrequency domain channel estimate 508 and the second frequency domainchannel estimate 528.

Referring again to the first diversity path, the multiplier 512 isoperable to multiply an output of FFT block 506 with the first frequencydomain equalizer coefficients 511. However, in another embodiment, themultiplier 518 simply passes through the first frequency domainequalizer coefficients 511. Then, the IFFT block 514 is operable toconvert the first frequency domain equalizer coefficients 511, asoperated upon by multiplier 512, to the time domain to produce firsttime domain equalizer coefficients. Next, the tap ordering block 516 isoperable to order the first time domain equalizer coefficients toproduce tap ordered time domain equalizer coefficients to the timedomain equalizer 518. Time domain equalizer 518 is operable to equalizethe first time domain data symbols using the first time domain equalizercoefficients received from tap ordering block 516.

Referring again to the second diversity path, the multiplier 530 isoperable to multiply the second frequency domain equalizer coefficients513 with an output received from FFT block 526. In another embodiment,the multiplier block 530 is operable to simply pass through the secondfrequency domain equalizer coefficients 513. The IFFT block 532 isoperable to convert its input from the frequency domain to the timedomain to produce second time domain equalizer coefficients. The tapordering block 534 is operable to tap order the second time domainequalizer coefficients to produce an output of time domain equalizer.The time domain equalizer 536 is operable to equalize the second timedata symbols using the second time domain equalizer coefficients.Finally, combiner 538 is operable to combine the equalized first timedomain data symbols received from the first time domain equalizer 518and the second equalized time domain data symbols received from timedomain equalizer 536 to produce a composite time domain data symbols540.

According to another aspect of the baseband processing module 222 ofFIG. 5, the CPP/channel estimation block 504 is operable to cluster pathprocess the first time domain training signals of the first time domainsignal 502. Cluster path processing (CPP) is an operation that processesmulti-path signal components that are relatively close to one another intime. A complete description of how cluster path processing is performedis described in co-pending patent application Ser. No. 11/173,854 filedJun. 30, 2005 and entitled METHOD AND SYSTEM FOR MANAGING, CONTROLLING,AND COMBINING SIGNALS IN A FREQUENCY SELECTIVE MULTIPATH FADING CHANNEL,which is incorporated herein by reference in its entirety. With thecluster path processing operations completed, the CPP/channel estimationblock 504 is operable to produce the first time domain channel estimatebased upon cluster path processed first time domain training symbols.Further, with the second diversity path, the CPP/channel estimationblock 522 may be operable to cluster path process the second time domaintraining symbols of the second time domain signal 522. Then, theCPP/channel estimation block 524 is operable to produce the second timedomain channel estimate based upon the cluster path process second timedomain training symbols.

In its operations, the MMSE weight calculation block 510 is operable toperform a MMSE algorithm on the first frequency domain equalizercoefficients 508 and the second frequency domain equalizer coefficients528 to produce the first frequency domain equalizer coefficients 511 andthe second frequency domain equalizer coefficients 513. Oneimplementation of these operations is described below. Other operationsmay be used to generate equalizer coefficients according to the presentinvention that differ from those described below.

With the particular implementation described herein, in the time domain,a matrix signal model at each antenna servicing the dual diversity pathstructure of FIG. 5 may be characterized as:

$\begin{matrix}{{y_{i} = {{{H_{i}x} + {n_{i}\mspace{31mu} i}} = 1}},2} & \left( {{Eq}.\mspace{14mu} 1} \right)\end{matrix}$

The channel matrix H_(i) can be modeled as a circulant matrix whichsatisfies

H ₁ =F ⁻¹ Λ ₁ F;H ₂ =F ⁻¹ Λ ₂ F  (Eq. 2)

where F is the orthogonal discrete Fourier transform matrix.

By multiplying by matrix F at both sides of the Eq. (1), a frequencydomain channel model is represented as:

Y _(i) =Fy _(i)=Λ^(i) X+N _(i)  (Eq. 3)

where X=Fx;N_(i)=Fn_(i)i=1,2

The channel model may be considered at the k-th subcarrier in thefrequency domain as:

$\begin{matrix}{{{Y\lbrack k\rbrack} = {{\Lambda_{k}{X\lbrack k\rbrack}} + {N\lbrack k\rbrack}}}{where}} & \left( {{Eq}.\mspace{14mu} 4} \right) \\{{{Y\lbrack k\rbrack} = \begin{bmatrix}{Y_{1}\lbrack k\rbrack} \\{Y_{2}\lbrack k\rbrack}\end{bmatrix}},{{{\Lambda_{k}\begin{bmatrix}\Lambda_{k}^{1} \\\Lambda_{k}^{2}\end{bmatrix}}\mspace{14mu} {and}\mspace{14mu} {N\lbrack k\rbrack}} = \begin{bmatrix}{N_{1}\lbrack k\rbrack} \\{N_{2}\lbrack k\rbrack}\end{bmatrix}}} & \left( {{Eq}.\mspace{14mu} 5} \right)\end{matrix}$

are 2×1 vectors.

The MMSE optimum weight at the k-th subcarrier is therefore representedby:

C[k]=E(Y[k]*Y[k] ^(T))⁻¹ E(Y[k]*X)=(Λ_(k)*Λ_(k) ^(T) +C_(nn))⁻¹Λ_(k)  (Eq. 6)

Thus, the estimated transmitted signal is given as

$\begin{matrix}{{\overset{\Cap}{X}\lbrack k\rbrack} = {{{C\lbrack k\rbrack}^{H}{Y\lbrack k\rbrack}} = \frac{\underset{{ant}\; 1}{\left( \underset{\_}{n\; 1*\Lambda_{k}^{1^{*}}{Y_{1}\lbrack k\rbrack}} \right.} + \underset{{ant}\; 2}{\underset{\_}{n\; 2*\Lambda_{k}^{2^{*}}{Y_{2}\lbrack k\rbrack}}}}{{{\Lambda_{k}^{1}}^{2}n\; 2} + {{\Lambda_{k}^{2}}^{2}n\; 1} + {n\; 1n\; 2}}}} & \left( {{Eq}.\mspace{14mu} 7} \right)\end{matrix}$

After simplifying Eq (7), the MMSE-FDE weight(s) for dual diversity pathconfiguration of FIG. 5 is given as:

$\begin{matrix}{{{C_{k}^{i} = \frac{\left( \frac{\sigma_{s}}{\sigma_{n}^{i}} \right)^{2}\Lambda_{k}^{i^{*}}}{1 + {\sum\limits_{l = 1}^{2}{\left( \frac{\sigma_{s}}{\sigma_{n}^{i}} \right)^{2}{\Lambda_{k}^{l}}^{2}}}}};{i = 1}},{{2\mspace{31mu} k} = 1},{2\mspace{11mu} \ldots \mspace{11mu} N}} & \left( {{Eq}.\mspace{14mu} 8} \right)\end{matrix}$

The time domain signal after Equalization is given by:

$\begin{matrix}\begin{matrix}{z = {F^{- 1}{CY}}} \\{= {{\underset{FD\_ EQ1}{\underset{}{F^{- 1}C^{1}\Lambda_{1}{FH}_{1}}}x} + {\underset{FD\_ EQ2}{\underset{}{F^{- 1}C^{2}\Lambda_{2}{FH}_{2}}}x} +}} \\{{{F^{- 1}C^{1}N_{1}} + {F^{- 1}C^{2}N_{2}}}}\end{matrix} & \left( {{Eq}.\mspace{14mu} 9} \right) \\\begin{matrix}{z = {F^{- 1}{CY}}} \\{= {\underset{Proposed\_ EQ1}{\underset{}{{F^{- 1}\left( C^{1} \right)} \otimes y}} + \underset{Proposed\_ EQ2}{\underset{}{{F^{- 1}\left( C^{2} \right)} \otimes y}} +}} \\{{{F^{- 1}C^{1}N_{1}} + {F^{- 1}C^{2}N_{2}}}}\end{matrix} & \left( {{Eq}.\mspace{14mu} 10} \right)\end{matrix}$

FIG. 6 is a block diagram illustrating equalization components of abaseband processing module according to a first embodiment of thepresent invention. The components of the baseband processing module 222are operable to receive a time domain signal 602 from an RF front endsuch as was illustrated in FIG. 2. The time domain signal 602 includestime domain training symbols and time domain data symbols. Thecomponents of FIG. 6 include channel estimation block 604, an FFT block606, a weight calculator block 610, an IFFT block 614, a tap orderingblock 616, and a time domain equalizer 618. The channel estimation block604 is operable to process the time domain training symbols of the timedomain signal 602 to produce a time domain channel estimate 603. The FFTblock 606 is operable to convert the time domain channel estimate 603 tothe frequency domain to produce a frequency domain channel estimate 608.The weight calculation block 610 is operable to produce frequency domainequalizer coefficients based upon the frequency domain channel estimate608 and noise variation estimation received from noise variationestimation block 602. Multiplier 612 receives the frequency domainequalizer coefficient 611 and the receiving input from the FFT block606. The multiplier 612 produces an output to IFFT block 614 thatconverts the frequency domain equalizer coefficient 611, as may havebeen modified by multiplier 612, to produce time domain equalizercoefficients. Tap ordering block 616 tap orders the time domainequalizer coefficients and produces the tap ordered time domainequalizer coefficients to time domain equalizer 616. The time domainequalizer 616 is operable to equalize the time domain data symbols ofthe time domain signal 602 using the time domain equalizer coefficientsto produce equalized time domain symbols 640.

The channel estimation block 604 may also perform cluster pathprocessing operations as were previously described with reference toFIG. 5. When performing cluster path processing operations to producethe time domain training symbols, the CPP/channel estimation block 604may produce the time domain channel estimate based upon the cluster pathprocessed time domain training symbols. The MMSE weight calculationblock 610 may perform MMSE algorithm on the frequency domain equalizercoefficients to produce the frequency domain equalizer coefficients.

FIG. 7 is a flow chart illustrating equalization operations according toan embodiment of the present invention. The operation 700 commences withoperations for each of at least two diversity paths (Step 702). As waspreviously described with reference to FIG. 3, a radio may include aplurality of RF front ends 302-308, each servicing a respectivediversity path. Thus, referring again to FIG. 7, operations 704-708 areperformed for each diversity path. In particular, for each diversitypath, the baseband processing module receives a corresponding timedomain signal that includes corresponding time domain training symbolsand corresponding time domain data symbols.

With reference to a first diversity path, operation includes receiving afirst time domain signal that includes first time domain trainingsymbols and first time domain data symbols. Operation then includesprocessing the first time domain training symbols to produce a firsttime domain channel estimate (Step 706). Further, operation includesconverting the time domain channel estimate to the frequency domain toproduce a first frequency domain channel estimate (Step 708).

With respect to a second diversity path, operation includes receiving asecond time domain signal that includes second time domain trainingsymbols and second time domain data symbols (Step 704). Operation forthe second diversity path further includes processing the second timedomain training symbols to produce a second time domain channel estimate(Step 706). Further, operation includes converting the second timedomain channel estimate to the frequency domain to produce a secondfrequency domain channel estimate (Step 708).

When the operations of Steps 702-708 have been completed for eachdiversity path, operation proceeds to Step 710 where frequency domainequalizer coefficients are produced for each of a plurality of diversitypaths. For the particular example of the structure of FIG. 5 thatincludes two diversity paths, the operation at Step 710 includesproducing first frequency domain equalizer coefficients and secondfrequency domain equalizer coefficients based upon the first frequencydomain channel estimate and the second frequency domain channelestimate. Operation then includes converting the frequency domainequalizer coefficients to time domain equalizer coefficients (Step 712).For the particular case of a first and a second diversity path, theoperation at Step 712 would include converting the first frequencydomain equalizer coefficients to the time domain to produce first timedomain equalizer coefficients and converting the second frequency domainequalizer coefficients to the time domain to produce second time domainequalizer coefficients.

Operation then includes, for each diversity path, time domain equalizingrespective time domain data symbols (Step 714). For the particular caseof a first and a second diversity path, the operations of Step 714include equalizing the first time domain data symbols using the firsttime domain equalizer coefficients and equalizing the second time domaindata symbols using the second time domain equalizer coefficients.Finally, operation includes combining the equalized time domain datasymbols from a plurality of diversity paths (Step 716). For theparticular case of the first and second diversity paths, the operationof Step 716 includes combining the equalized first time domain datasymbols and the second equalized time domain data symbols to producecomposite time domain data symbols.

The operations 702-716 are repeated each time new equalizer coefficientsare produced based upon received physical layer frames that includetraining symbols. In many RF receivers, the operations 700 of FIG. 7 arerepeated for each received physical layer frame. However, in otherembodiments, channel estimation is performed periodically based upondetected changes of channel conditions or when a time constraint is met.

The operations at Step 706 may include cluster path processing as hasbeen previously described. When cluster processing is performed, thetime domain channel estimate include cluster path processed time domaintraining symbols. Fast Fourier transformations are employed inconverting from the time domain to the frequency domain while InverseFast Fourier transformations are to employed to convert from thefrequency domain to the time domain. The operations at Step 710 mayinclude using an MMSE algorithm to produce the frequency domainequalizer coefficients based upon the channel estimates received. Theoperations of FIG. 7 may support various types of systems includingcellular wireless communication systems, wireless metropolitan areacommunication systems (such as the WiMAX) standards, WLAN communicationoperations, and WPAN communication operations.

FIG. 8 is a flow chart illustrating equalization operations according toan embodiment of the present invention. Operation 800 includes firstreceiving a time domain signal that includes time domain trainingsymbols and time domain data symbols (Step 802). Operation continueswith processing the time domain training symbols to produce a timedomain channel estimate (Step 804). Operation continues with convertingthe time domain channel estimate to the frequency domain to produce afrequency domain channel estimate (Step 806).

Operation further includes producing frequency domain equalizercoefficients based upon the frequency domain channel estimate producedat Step 806 (Step 808). Then, operation includes converting thefrequency domain equalizer coefficients to the time domain to producetime domain equalizer coefficients (Step 810). Operation concludes withequalizing the time domain data symbols using the time domain equalizercoefficients produced at Step 810 (Step 812). From Step 812 operationends. Of course, the operations 800 of FIG. 8 may be repeated for eachreceived physical layer frame that includes training symbols and datasymbols. The various specific implementations that were previouslydescribed with FIGS. 1-7 may be employed with the operations 800 of FIG.8 as well and will not be described herein further with respect to FIG.8.

FIG. 9A is a block diagram illustrating a Multiple-Input-Single-Output(MISO) transmission system supported by equalization operationembodiments of the present invention operate. A transmitter 902 of thesystem includes multiple antennas 904 and 906, each of which transmitsan information signal. These information signals S₁ and S₂ may be SpaceTime Transmit Diversity (STTD) signals, the formation and transmissionof which is generally known and will not be described further other thanas they relate to the present invention. In some operations, the firstinformation signal S₁ carries the same data as the second informationsignal S2. The information signals S₁ and S₂ transmitted via antennas904 and 906 are operated upon by channel 908 and received together as amerged information signal via antenna 912 by RF receiver 910. The RFreceiver 910 operates upon this merged information signal, as will bedescribed further with reference to FIGS. 10 and 11.

FIG. 9B is a block diagram illustrating a Multiple-Input-Multiple-Output(MIMO) transmission system supported by equalization operationembodiments of the present invention operate. A transmitter 952 of thesystem includes multiple antennas 954 and 956, each of which transmits arespective information signal. These information signals S₁ and S₂ carrydiffering data, i.e., a first information signal S₁ carries differingdata than does second information signal S₂. The information signals S₁and S₂ transmitted via antennas 954 and 956 are operated upon by channel958 and received together as merged information signals by antennas 962and 964 by RF receiver 960. Because of the operations of the channel958, each of the antennas receives a respective merged informationsignal that is a combination of the transmitted signals S₁ and S₂. TheRF receiver 960 operates upon these merged information signals S₁ andS₂, as will be described further with reference to FIGS. 12 and 13.

FIG. 10 is a block diagram illustrating equalization components of abaseband processing module according to a third embodiment of thepresent invention. The components of the baseband processing module 222are operable to receive a merged information 1002 from an RF front endsuch as was illustrated in FIG. 2. The merged information signal 1002includes a first information signal and a second information signal,each of the first and second information signals having time domaintraining symbols and data symbols and is, of course, in the time domainupon receipt. The baseband processing module include at least onechannel estimator 1004 and 1008 operable to process the firstinformation signal time domain training symbols and the secondinformation signal time domain training symbols to produce a firstinformation signal time domain channel estimate and a second informationsignal time domain channel estimate. The baseband processing module 222further includes at least one Fast Fourier Transformer 1006 and 1010operable to transform the first information signal time domain channelestimate and the second information signal time domain channel estimateto the frequency domain to produce a first information signal frequencydomain channel estimate and a second information signal frequency domainchannel estimate, respectively. The baseband processing module 222further includes a weight calculator 1012 operable to produce firstfrequency domain equalizer coefficients and second frequency domainequalizer coefficients based upon the first information signal frequencydomain channel estimate and the second information signal frequencydomain channel estimate. The baseband processing module 222 alsoincludes at least one Inverse Fast Fourier Transformer 1016 and 1022operable to transform the first frequency domain equalizer coefficientsand the second frequency domain equalizer coefficients to the timedomain to produce first time domain equalizer coefficients and secondtime domain equalizer coefficients, respectively. Further, the basebandprocessing module further includes at least one equalizer 1020 and 1026operable to equalize the merged information signal time using the firsttime domain equalizer coefficients to produce equalized firstinformation signal data symbols and to equalize the merged informationsignal time using the first time domain equalizer coefficients toproduce equalized second information signal data symbols.

In particular, channel estimation block 1004 is operable to process thefirst information signal time domain training symbols of the mergedinformation 1002 to produce a first information signal time domainchannel estimate. The second information signal estimation block 1008 isoperable to process the second information signal time domain trainingsymbols of the merged information signal 1002 to produce a secondinformation signal domain channel estimate. FFT block 1006 is operableto convert the first information signal time domain channel estimate tothe frequency domain to produce a first information signal frequencydomain channel estimate. FFT block 1010 is operable to convert thesecond information signal time domain channel estimate to the frequencydomain to produce a second information signal frequency domain channelestimate. The weight calculation block 1012 is operable to produce firstand second frequency domain equalizer coefficients based upon the firstinformation signal frequency domain channel estimate, the secondinformation signal frequency domain channel estimate, and noisevariation estimation received from noise variation estimation block1014.

IFFT block 1016 converts the first frequency domain equalizercoefficients to the time domain to produce first time domain equalizercoefficients. Tap ordering block 1018 tap orders the first time domainequalizer coefficients and produce tap ordered first time domainequalizer coefficients to time domain equalizer 1020 The time domainequalizer 1020 is operable to equalize the merged information signal1002 using the time domain equalizer coefficients to produce equalizedfirst information signal data symbols.

IFFT block 1022 converts the second frequency domain equalizercoefficients to the time domain to produce second time domain equalizercoefficients. Tap ordering block 1024 tap orders the second time domainequalizer coefficients and produce tap ordered second time domainequalizer coefficients to time domain equalizer 1026 The time domainequalizer 1026 is operable to equalize the merged information signal1002 using the time domain equalizer coefficients to produce equalizedsecond information signal data symbols.

Despreader 1030 is operable to despread the equalized first informationsignal data symbols. Despreader 1028 is operable to despread theequalized second information signal data symbols. STTD decoder 1032 isoperable to STTD decode the despread equalized first information signaldata symbols and the despread equalized second information signal datasymbols.

The channel estimation blocks 1004 and/or 1008 may also perform clusterpath processing operations as were previously described with referenceto FIG. 5. When performing cluster path processing operations to producethe time domain training symbols, the CPP/channel estimation blocks 1004and 1008 may produce the time domain channel estimates based upon thecluster path processed time domain training symbols. The MMSE weightcalculation block 1012 may perform MMSE algorithm on the frequencydomain equalizer coefficients to produce the frequency domain equalizercoefficients.

FIG. 11 is a flow chart illustrating equalization operations accordingto the fourth embodiment of the present invention. Operation 1100includes first receiving a merged information signal that includes afirst information signal and a second information signal, each of thefirst and second information signals having time domain training symbolsand data symbols (Step 1102). Operation continues with estimatingenergies of the information signals and optionally, the energy of atleast one interfering signal present in the merged information signal(Step 1104). Operation next includes processing the first informationsignal time domain training symbols and the second information signaltime domain training symbols to produce a first information signal timedomain channel estimate and a second information signal time domainchannel estimate (Step 1106). Operation continues with converting thefirst information signal time domain channel estimate and the secondinformation signal time domain channel estimate to the frequency domainto produce a first information signal frequency domain channel estimateand a second information signal frequency domain channel estimate,respectively (Step 1108). Operation next includes producing firstfrequency domain equalizer coefficients and second frequency domainequalizer coefficients based upon the first information signal frequencydomain channel estimate and the second information signal frequencydomain channel estimate (Step 1110). Operation continues with convertingthe first frequency domain equalizer coefficients and the secondfrequency domain equalizer coefficients to the time domain to producefirst time domain equalizer coefficients and second time domainequalizer coefficients, respectively (Step 1112).

Then, operation includes equalizing the merged information signal timeusing the first time domain equalizer coefficients to produce equalizedfirst information signal data symbols and equalizing the mergedinformation signal time using the first time domain equalizercoefficients to produce equalized second information signal data symbols(Step 1114). Operation continues with despreading and combining theequalized data symbols (Step 1116). From Step 1116 operation ends. Ofcourse, the operations 1100 of FIG. 111 may be repeated for eachreceived physical layer frame that includes training symbols and datasymbols.

The operations of Step 1112 may be performed on an STTD signal. In suchcase, the first information signal data symbols and the secondinformation signal data symbols carry common data. In this case, themethod 1100 includes STTD decoding the equalized first informationsignal data symbols and the equalized second information signal datasymbols. The operations of Step 1116 may include despreading theequalized first information signal data symbols and despreading theequalized second information signal data symbols prior to STTD decodingthe despread equalized first information signal data symbols and thedespread equalized second information signal data symbols as wasillustrated in FIG. 10.

Referring now to all of FIGS. 9A, 10, and 11, a baseband processingmodule 222 and operations of the present invention may implement thefollowing MISO equations and techniques. In particular, MISO operations1100 of FIG. 11 and implemented by the baseband processing module 222(in particular the MMSE weight calculation block 1012 of FIG. 10) mayoperate consistent with the following signal model(s). A signal model atthe k^(th)-subcarrier in the frequency domain may be modeled as:

Y[k]=H ₁ [k]S ₁ +H ₂ [k]S ₂ +N  (Eq. 11)

By treating the second information signal S₂ as interference to thefirst information signal S₁, the FDE-IS for the first information signalS₁ with MMSE optimum weight at each sub-carrier is given as

$\begin{matrix}\begin{matrix}{{W\lbrack k\rbrack} = {{E\left( {{Y\lbrack k\rbrack}^{*}{Y\lbrack k\rbrack}^{T}} \right)}^{- 1}{E\left( {{Y\lbrack k\rbrack}^{*}S_{1}} \right)}}} \\{= {\left( {{{H_{1}\lbrack k\rbrack}^{*}{H_{1}\lbrack k\rbrack}^{T}} + {{H_{2}\lbrack k\rbrack}^{*}{H_{2}\lbrack k\rbrack}^{T}} + C_{nn}} \right)^{- 1}{H_{1}\lbrack k\rbrack}}}\end{matrix} & \left( {{Eq}.\mspace{14mu} 12} \right)\end{matrix}$

Similarly, by treating the first information signal S₁ as interferenceto the second information signal S₂, the FDE-IS for the secondinformation signal S₂ with MMSE optimum weight at each sub-carrier isgiven as:

$\begin{matrix}\begin{matrix}{{C\lbrack k\rbrack} = \begin{bmatrix}C_{k}^{1} \\C_{k}^{2}\end{bmatrix}} \\{= {{E\left( {{Y\lbrack k\rbrack}^{*}{Y\lbrack k\rbrack}^{T}} \right)}^{- 1}{E\left( {{Y\lbrack k\rbrack}^{*}S_{2}} \right)}}} \\{= {\left( {{{H_{2}\lbrack k\rbrack}^{*}{H_{2}\lbrack k\rbrack}^{T}} + {{H_{1}\lbrack k\rbrack}^{*}{H_{1}\lbrack k\rbrack}^{T}} + C_{nn}} \right)^{- 1}{H_{2}\lbrack k\rbrack}}}\end{matrix} & \left( {{Eq}.\mspace{14mu} 13} \right)\end{matrix}$

Then, using IFFT operations, the coefficient of the time domainequalizers (at Step 1112) is achieved.

FIG. 12 is a block diagram illustrating equalization components of abaseband processing module according to a fourth embodiment of thepresent invention. These components of the baseband processing module222 perform equalization operations according to one or more embodimentsthe present invention. Of course, a baseband processing module 222 wouldinclude additional components in addition to as those illustrated inFIG. 12. The functional blocks of FIG. 12 may be implemented indedicated hardware, general purpose hardware, software, or a combinationof dedicated hardware, general purpose hardware, and software.

The components of the baseband processing module 222 of FIG. 12 includefirst diversity path components, second diversity path components, andshared components. As was described with reference to FIGS. 3 and 9B, anRF transceiver (transmitter/receiver), may include a plurality ofreceive signal paths. The plurality of receive signal paths operate upona MIMO transmitted signal. According to the embodiment of FIG. 12, thefunctional components operate upon different versions of the MIMOtransmitted signal as was previously described with reference to FIG.9B.

The first diversity path component includes a first information signalcluster path processor/channel estimation block 1204, a second desiredsignal cluster path processor/channel estimation block 1208, a FastFourier Transform (FFT) block 1206, a Fast Fourier Transform (FFT) block1212, Inverse Fast Fourier Transform (IFFT) block 1216, tap orderingblock 1218, time domain equalizer 1220, Inverse Fast Fourier Transform(IFFT) block 1222, tap ordering block 1224, and time domain equalizer1226. The second diversity path components include first informationsignal cluster path processor/channel estimation block 1234, a seconddesired signal cluster path processor/channel estimation block 1238, aFast Fourier Transform (FFT) block 1236, a Fast Fourier Transform (FFT)block 1240, Inverse Fast Fourier Transform (IFFT) block 1248, tapordering block 1250, time domain equalizer 1252, Inverse Fast FourierTransform (IFFT) block 1242, tap ordering block 1244, and time domainequalizer 1246.

The shared processing blocks of the RF receiver of FIG. 12 include ajoint Delay Locked Loop (DLL) 1230, a Minimum Mean Square Error (MMSE)weight calculation block 1212, a noise variance estimation block 1214,combiners 1254 and 1256, despreaders 1258 and 1260, and STTD decoder1262. Generally, the joint DLL 1230 is controlled by CPP operations thatset the sampling positions of the CPP/channel estimation blocks 1204,1208, 1234, and 1238.

In its operations, the first diversity path operates upon a first timedomain signal (first merged information signal) 1202. The first timedomain signal 1202 includes first information signal time domaintraining symbols and data symbols and second information signal timedomain training symbols and data symbols. As is generally known, framesof transmitted symbols in an RF system typically include a preamble thathas training symbols and a payload portion that carries data symbols.The training symbols are used by channel estimation operations toproduce equalizer coefficients that are then used for equalization ofthe data symbols. The first information signal CPP/channel estimationblock 1204 is operable to process first information signal time domaintraining symbols of the first time domain signal 1202 to produce a firstinformation signal time domain channel estimate. The second informationsignal CPP/channel estimation block 1208 is operable to process secondinformation signal time domain training symbols of the first time domainsignal 1202 to produce a second information signal time domain channelestimate. In producing the their respective channel estimates, theCPP/channel estimation blocks 1204 and 1208 may receive estimates ofenergies of the information and second information signals from aninformation signal energy estimation block and an interfering energyestimation block, respectively (not shown). The CPP/channel estimationblocks 1204 and/or 1208 is/are operable to perform cluster pathprocessing. The FFT block 1206 is operable to convert the firstinformation signal time domain channel estimate to the frequency domainto produce a first information signal frequency domain channel estimate.The FFT block 1212 is operable to convert the second information signaltime domain channel estimate to the frequency domain to produce a secondinformation signal frequency domain channel estimate.

Likewise, the second diversity path operates upon a second time domainsignal (second merged information signal) 1232. The second time domainsignal 1232 includes first information signal time domain trainingsymbols and data symbols and second information signal time domaintraining symbols and data symbols. The first information signalCPP/channel estimation block 1234 is operable to process the firstinformation signal time domain training symbols of the second timedomain signal 1232 to produce a second information signal time domainchannel estimate. The second information signal CPP/channel estimationblock 1238 is operable to process second information signal time domaintraining symbols of the second time domain signal 1232 to produce asecond information signal time domain channel estimate. In producingtheir respective channel estimates, the CPP/channel estimation blocks1234 and 1238 may receive estimates of energies of the information andsecond information signals from first information signal energyestimation block and interfering energy estimation block, respectively(not shown). The CPP/channel estimation blocks 1234 and/or 1238 is/areoperable to perform cluster path processing. The FFT block 1236 isoperable to convert the second information signal time domain channelestimate to the frequency domain to produce a second information signalfrequency domain channel estimate. The FFT block 1240 is operable toconvert the second information signal time domain channel estimate tothe frequency domain to produce a second information signal frequencydomain channel estimate.

The MMSE/weight calculation block 1212 is operable to produce firstfrequency domain equalizer coefficients, second frequency domainequalizer coefficients, third frequency domain equalizer coefficients(first frequency domain equalizer coefficients for the second diversitypath), and fourth frequency domain equalizer coefficients (secondfrequency domain equalizer coefficients for the second diversity path)based upon the first information signal frequency domain channelestimate and the first second information signal frequency domainchannel estimate received from the first diversity path and the firstinformation signal frequency domain channel estimate, the secondinformation signal frequency domain channel estimate received from thesecond diversity path, and noise variance estimation parameters receivedfrom noise variance estimation block 1214 and.

Referring again to the first diversity path, the IFFT block 1216 isoperable to convert the first frequency domain equalizer coefficients tothe time domain to produce first time domain equalizer coefficients.Next, the tap ordering block 1218 is operable to order the first timedomain equalizer coefficients to produce tap ordered first time domainequalizer coefficients to the time domain equalizer 1220. Time domainequalizer 1220 is operable to equalize the first merged informationsignal (time domain signal 1202) using the tap ordered first time domainequalizer coefficients received from tap ordering block 1216. The IFFTblock 1222 is operable to convert the second frequency domain equalizercoefficients to the time domain to produce second time domain equalizercoefficients. Next, the tap ordering block 1224 is operable to order thesecond time domain equalizer coefficients to produce tap ordered secondtime domain equalizer coefficients to the time domain equalizer 1226.Time domain equalizer 1226 is operable to equalize the first mergedinformation signal (time domain signal 1202) using the tap orderedsecond time domain equalizer coefficients received from tap orderingblock 1224.

Referring again to the second diversity path, the IFFT block 1242 isoperable to convert the third frequency domain equalizer coefficients(first frequency domain equalizer coefficients for the second diversitypath) to the time domain to produce third time domain equalizercoefficients (first time domain equalizer coefficients for the seconddiversity path). Next, the tap ordering block 1244 is operable to orderthe third time domain equalizer coefficients to produce tap orderedthird time domain equalizer coefficients to the time domain equalizer1246. Time domain equalizer 1246 is operable to equalize the secondmerged information signal (time domain signal 1232) using the tapordered third time domain equalizer coefficients received from tapordering block 1244. The IFFT block 1248 is operable to convert thefourth frequency domain equalizer coefficients (second frequency domainequalizer coefficients for the second diversity path) to the time domainto produce fourth time domain equalizer coefficients (second time domainequalizer coefficients for the second diversity path). Next, the tapordering block 1250 is operable to order the fourth time domainequalizer coefficients to produce tap ordered fourth time domainequalizer coefficients to the time domain equalizer 1252. Time domainequalizer 1252 is operable to equalize the second merged informationsignal (time domain signal 1232) using the tap ordered fourth timedomain equalizer coefficients received from tap ordering block 1250.

Combiner 1254 is operable to combine the outputs of time domainequalizers 1226 and 1252 while combiner 1256 is operable to combine theoutputs of time domain equalizers 1220 and 1246. Despreader 1258 isoperable to despread the output of combiner 1254 while despreader 1260is operable to despread the output of combiner 1256. Further, in someembodiments, when STTD is employed, STTD decoder is operable to STTDdecode the outputs of despreaders 1258 and 1260.

FIG. 13 is a flow chart illustrating equalization operations accordingto the third embodiment of the present invention. The operation 1300commences with operations for each of at least two diversity paths (Step1302). As was previously described with reference to FIGS. 3, 5, and 12,a radio may include a plurality of RF front ends 302-308, each servicinga respective diversity path. Thus, referring again to FIG. 13,operations 1304-1314 are performed for each diversity path. Inparticular, for each diversity path, the baseband processing modulereceives a merged information signal that includes a first informationsignal and a second information signal, each of the first and secondinformation signals having time domain training symbols and datasymbols.

With reference to a first diversity path, operation includes receiving afirst time domain information signal (first merged information signal).The first diversity path then estimates energies of first and secondinformation signals and, in some cases, one or more interfering signalspresent in the time domain merged information signal (Step 1306).Operation then includes processing the first information signal(dominant interferer) time domain training symbols to produce a firstinformation signal time domain channel estimate (Step 1308). Further,operation includes converting the first information signal time domainchannel estimate to the frequency domain to produce a first informationsignal frequency domain channel estimate (Step 1310). Operation thenincludes processing the second information signal time domain trainingsymbols to produce a second information signal time domain channelestimate (Step 1312). Further, operation includes converting the secondinformation signal time domain channel estimate to the frequency domainto produce a second information signal frequency domain channel estimate(Step 1314).

With reference to a second diversity path, operation includes receivinga second time domain signal (second merged information signal). Thesecond diversity path then estimates energies of first and secondinformation signals and, in some cases, one or more interfering signalspresent in the time domain merged information signal (Step 1306).Operation then includes processing the first information signal timedomain training symbols to produce a first information signal timedomain channel estimate (Step 1308). Further, operation includesconverting the first information signal time domain channel estimate tothe frequency domain to produce a first information signal frequencydomain channel estimate (Step 1310). Operation then includes processingthe second information signal time domain training symbols to produce asecond information signal time domain channel estimate (Step 1312).Further, operation includes converting the second information signaltime domain channel estimate to the frequency domain to produce a secondinformation signal frequency domain channel estimate (Step 1314).

Steps 1304 through 1314 may be performed for more than two diversitypaths. When the operations of Steps 1304-1314 have been completed foreach diversity path, operation proceeds to Step 1316 where one or moresets of frequency domain equalizer coefficients are produced for each ofthe plurality of diversity paths. For the particular example of thestructure of FIG. 12 that includes two diversity paths, the operation atStep 1316 includes producing first and second frequency domain equalizercoefficients for each diversity path based upon the frequency domainchannel estimates. Operation then includes converting the frequencydomain equalizer coefficients to time domain equalizer coefficients(Step 1318). Operation then includes, for each diversity path, timedomain equalizing respective time domain data symbols (Step 1320).Finally, operation includes combining at least some of the equalizedtime domain data symbols from the plurality of diversity paths (Step1322). These operations may include STTD combining operations.

The operations 1302-1322 are repeated each time new equalizercoefficients are produced based upon received physical layer frames thatinclude training symbols. In many RF receivers, the operations 1300 ofFIG. 13 are repeated for each received physical layer frame. However, inother embodiments, channel estimation is performed periodically basedupon detected changes of channel conditions or when a time constraint ismet.

The operations at Steps 1308 and 1312 may include cluster pathprocessing as has been previously described. When cluster processing isperformed, the time domain channel estimates include cluster pathprocessed time domain training symbols. Fast Fourier transformations areemployed in converting from the time domain to the frequency domainwhile Inverse Fast Fourier transformations are to employed to convertfrom the frequency domain to the time domain. The operations at Step1316 may include using an MMSE algorithm to produce the frequency domainequalizer coefficients based upon the channel estimates received. Theoperations of FIG. 13 may support various types of systems includingcellular wireless communication systems, wireless metropolitan areacommunication systems (such as the WiMAX) standards, WLAN communicationoperations, and WPAN communication operations.

The operations of FIG. 13 may be performed on received MIMO signals. Thefollowing equations (viewed in conjunction with the operations of FIG.13, the baseband processing module 222 of FIG. 12, and the channel modelof FIG. 10B) may be employed by embodiments of the present inventionupon received MIMO signals. The MIMO signal model may be characterizedas:

Y[k]=H ₁ [k]S ₁ +H ₂ [k]S ₂ +N  (Eq. 14)

By treating the second information signal S₂ signal as interference tothe first information signal S₁, the frequency domain equalizercoefficients for the first information signal S₁ signal with MMSEoptimum weight at each sub-carrier is given as:

$\begin{matrix}\begin{matrix}{{W\lbrack k\rbrack} = {{E\left( {{Y\lbrack k\rbrack}^{*}{Y\lbrack k\rbrack}^{T}} \right)}^{- 1}{E\left( {{Y\lbrack k\rbrack}^{*}S_{1}} \right)}}} \\{= {\left( {{{H_{1}\lbrack k\rbrack}^{*}{H_{1}\lbrack k\rbrack}^{T}} + {{H_{2}\lbrack k\rbrack}^{*}{H_{2}\lbrack k\rbrack}^{T}} + C_{nn}} \right)^{- 1}{H_{1}\lbrack k\rbrack}}}\end{matrix} & \left( {{Eq}.\mspace{14mu} 15} \right)\end{matrix}$

Similarly, by treating the first information signal S₁ signal asinterference to the second information signal S₂, the frequency domainequalizer coefficients for the second information signal S₂ with MMSEoptimum weight at each sub-carrier is given as:

$\begin{matrix}\begin{matrix}{{C\lbrack k\rbrack} = \begin{bmatrix}C_{k}^{1} \\C_{k}^{2}\end{bmatrix}} \\{= {{E\left( {{Y\lbrack k\rbrack}^{*}{Y\lbrack k\rbrack}^{T}} \right)}^{- 1}{E\left( {{Y\lbrack k\rbrack}^{*}S} \right)}}} \\{= {\left( {{{H_{2}\lbrack k\rbrack}^{*}{H_{2}\lbrack k\rbrack}^{T}} + {{H_{1}\lbrack k\rbrack}^{*}{H_{1}\lbrack k\rbrack}^{T}} + C_{nn}} \right)^{- 1}{H_{2}\lbrack k\rbrack}}}\end{matrix} & \left( {{Eq}.\mspace{14mu} 16} \right)\end{matrix}$

Then, using IFFT operations, the coefficient of the time domainequalizer are achieved. In more detail, we have

$\begin{matrix}{{H_{1}\lbrack k\rbrack} = {{\begin{bmatrix}{H_{11}\lbrack k\rbrack} \\{H_{12}\lbrack k\rbrack}\end{bmatrix}\mspace{31mu} {H_{2}\lbrack k\rbrack}} = \begin{bmatrix}{H_{21}\lbrack k\rbrack} \\{H_{22}\lbrack k\rbrack}\end{bmatrix}}} & \left( {{Eq}.\mspace{14mu} 17} \right)\end{matrix}$

By ignoring the subscript k, we have

$\begin{matrix}{W = {\begin{bmatrix}{{H_{11}}^{2} + {H_{21}}^{2} + {\sigma_{N\; 1}/S}} & {{H_{11}H_{12}^{*}} + {H_{21}H_{22}^{*}}} \\{{H_{12}H_{d\; 1}^{*}} + {H_{22}H_{I\; 1}^{*}}} & {{H_{12}}^{2} + {H_{22}}^{2} + \frac{\sigma_{N\; 2}}{S}}\end{bmatrix}^{- 1}\begin{bmatrix}H_{11} \\H_{12}\end{bmatrix}}} & \left( {{Eq}.\mspace{14mu} 18} \right) \\\begin{matrix}{W = \begin{bmatrix}W_{1} \\W_{2}\end{bmatrix}} \\{= {\begin{bmatrix}\frac{\left( {{H_{12}}^{2} + {H_{22}}^{2} + \frac{\sigma_{N\; 2}^{2}}{S}} \right)}{\det} & \frac{- \left( {{H_{11}H_{12}^{*}} + {H_{21}H_{22}^{*}}} \right)}{\det} \\\frac{- \left( {{H_{12}H_{11}^{*}} + {H_{22}H_{21}^{*}}} \right)}{\det} & \frac{\left( {{H_{11}}^{2} + {H_{21}}^{2} + \frac{\sigma_{N\; 1}^{2}}{S}} \right)}{\det}\end{bmatrix}\begin{bmatrix}H_{11} \\H_{12}\end{bmatrix}}}\end{matrix} & \left( {{Eq}.\mspace{14mu} 19} \right)\end{matrix}$

After weight simplification processing, we have:

$\begin{matrix}{W_{1} = {\alpha\left( {{{H_{22}}^{2}H_{11}} + {\frac{\sigma_{N\; 2}^{2}}{S}H_{11}} - {H_{21}H_{22}^{*}H_{12}}} \right)}} & \left( {{Eq}.\mspace{14mu} 20} \right) \\{\mspace{34mu} {= {{\alpha \left( {{H_{22}}^{2} + \frac{\sigma_{N\; 2}^{2}}{S} - \frac{H_{21}H_{22}^{*}H_{12}H_{11}^{*}}{{H_{11}}^{2}}} \right)}H_{11}}}} & \left( {{Eq}.\mspace{14mu} 21} \right) \\{\mspace{34mu} {= {{\alpha\beta}_{11}H_{11}}}} & \left( {{Eq}.\mspace{14mu} 22} \right) \\{W_{2} = {\alpha\left( {{{H_{21}}^{2}H_{12}} + {\frac{\sigma_{N\; 1}^{2}}{S}H_{12}} - {H_{22}H_{21}^{*}H_{11}}} \right)}} & \left( {{Eq}.\mspace{14mu} 23} \right) \\{\mspace{34mu} {= {{\alpha \left( {{H_{21}}^{2} + \frac{\sigma_{N\; 1}^{2}}{S} - \frac{H_{22}H_{21}^{*}H_{11}H_{12}^{*}}{{H_{12}}^{2}}} \right)}H_{12}}}} & \left( {{Eq}.\mspace{14mu} 24} \right) \\{\mspace{34mu} {= {{\alpha\beta}_{12}H_{12}}}} & \left( {{Eq}.\mspace{14mu} 25} \right) \\{C = {\begin{bmatrix}{{H_{11}}^{2} + {H_{21}}^{2} + \frac{\sigma_{N\; 1}^{2}}{S}} & {{H_{11}H_{12}^{*}} + {H_{21}H_{22}^{*}}} \\{{H_{12}H_{11}^{*}} + {H_{22}H_{21}^{*}}} & {{H_{12}}^{2} + {H_{22}}^{2} + \frac{\sigma_{N\; 2}^{2}}{S}}\end{bmatrix}^{- 1}\begin{bmatrix}H_{21} \\H_{22}\end{bmatrix}}} & \left( {{Eq}.\mspace{14mu} 26} \right) \\\begin{matrix}{C = \begin{bmatrix}C_{1} \\C_{2}\end{bmatrix}} \\{= {\begin{bmatrix}\frac{\left( {{H_{12}}^{2} + {H_{22}}^{2} + \frac{\sigma_{N\; 2}^{2}}{S}} \right)}{\det} & \frac{- \left( {{H_{11}H_{12}^{*}} + {H_{21}H_{22}^{*}}} \right)}{\det} \\\frac{- \left( {{H_{12}H_{11}^{*}} + {H_{22}H_{21}^{*}}} \right)}{\det} & \frac{\left( {{H_{11}}^{2} + {H_{21}}^{2} + \frac{\sigma_{N\; 1}^{2}}{S}} \right)}{\det}\end{bmatrix}\begin{bmatrix}H_{11} \\H_{12}\end{bmatrix}}}\end{matrix} & \left( {{Eq}.\mspace{14mu} 27} \right)\end{matrix}$

After weight simplification processing, we have:

$\begin{matrix}{C_{1} = {\alpha\left( {{{H_{12}}^{2}H_{21}} + {\frac{\sigma_{N\; 2}^{2}}{S}H_{21}} - {H_{11}H_{12}^{*}H_{22}}} \right)}} & \left( {{Eq}.\mspace{14mu} 28} \right) \\{= {{\alpha \left( {{H_{12}}^{2} + \frac{\sigma_{N\; 2}^{2}}{S} - \frac{H_{11}H_{12}^{*}H_{22}H_{21}^{*}}{{H_{21}}^{2}}} \right)}H_{21}}} & \left( {{Eq}.\mspace{14mu} 29} \right) \\{= {{\alpha\beta}_{21}H_{21}}} & \left( {{Eq}.\mspace{14mu} 30} \right) \\{C_{2} = {\alpha\left( {{{H_{11}}^{2}H_{22}} + {\frac{\sigma_{N\; 1}^{2}}{S}H_{22}} - {H_{12}H_{11}^{*}H_{21}}} \right)}} & \left( {{Eq}.\mspace{14mu} 31} \right) \\{= {{\alpha \left( {{H_{11}}^{2} + \frac{\sigma_{N\; 1}^{2}}{S} - \frac{H_{12}H_{11}^{*}H_{21}H_{22}^{*}}{{H_{22}}^{2}}} \right)}H_{22}}} & \left( {{Eq}.\mspace{14mu} 32} \right) \\{= {{\alpha\beta}_{12}H_{12}}} & \left( {{Eq}.\mspace{14mu} 33} \right) \\{{1/\alpha} = {{\left( {{H_{d\; 1}}^{2} + {H_{I\; 1}}^{2} + \frac{\sigma_{N\; 1}^{2}}{S}} \right)\left( {{H_{d\; 2}}^{2} + {H_{I\; 2}}^{2} + \frac{\sigma_{N\; 2}^{2}}{S}} \right)} - {\left( {{H_{d\; 1}H_{d\; 2}^{*}} + {H_{I\; 1}H_{I\; 2}^{*}}} \right)\left( {{H_{d\; 2}H_{d\; 1}^{*}} + {H_{I\; 2}H_{I\; 1}^{*}}} \right)}}} & \left( {{Eq}.\mspace{14mu} 34} \right)\end{matrix}$

As one of ordinary skill in the art will appreciate, the terms “operablycoupled” and “communicatively coupled,” as may be used herein, includedirect coupling and indirect coupling via another component, element,circuit, or module where, for indirect coupling, the interveningcomponent, element, circuit, or module does not modify the informationof a signal but may adjust its current level, voltage level, and/orpower level. As one of ordinary skill in the art will also appreciate,inferred coupling (i.e., where one element is coupled to another elementby inference) includes direct and indirect coupling between two elementsin the same manner as “operably coupled” and “communicatively coupled.”

The present invention has also been described above with the aid ofmethod steps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention.

The present invention has been described above with the aid offunctional building blocks illustrating the performance of certainsignificant functions. The boundaries of these functional buildingblocks have been arbitrarily defined for convenience of description.Alternate boundaries could be defined as long as the certain significantfunctions are appropriately performed. Similarly, flow diagram blocksmay also have been arbitrarily defined herein to illustrate certainsignificant functionality. To the extent used, the flow diagram blockboundaries and sequence could have been defined otherwise and stillperform the certain significant functionality. Such alternatedefinitions of both functional building blocks and flow diagram blocksand sequences are thus within the scope and spirit of the claimedinvention.

One of average skill in the art will also recognize that the functionalbuilding blocks, and other illustrative blocks, modules and componentsherein, can be implemented as illustrated or by discrete components,application specific integrated circuits, processors executingappropriate software and the like or any combination thereof.

Moreover, although described in detail for purposes of clarity andunderstanding by way of the aforementioned embodiments, the presentinvention is not limited to such embodiments. It will be obvious to oneof average skill in the art that various changes and modifications maybe practiced within the spirit and scope of the invention, as limitedonly by the scope of the appended claims.

1. A method for operating a Radio Frequency (RF) receiver comprising:receiving a merged information signal that includes a first informationsignal and a second information signal, each of the first and secondinformation signals having time domain training symbols and datasymbols; processing the first information signal time domain trainingsymbols and the second information signal time domain training symbolsto produce a first information signal time domain channel estimate and asecond information signal time domain channel estimate; converting thefirst information signal time domain channel estimate and the secondinformation signal time domain channel estimate to the frequency domainto produce a first information signal frequency domain channel estimateand a second information signal frequency domain channel estimate,respectively; producing first frequency domain equalizer coefficientsand second frequency domain equalizer coefficients based upon the firstinformation signal frequency domain channel estimate and the secondinformation signal frequency domain channel estimate; converting thefirst frequency domain equalizer coefficients and the second frequencydomain equalizer coefficients to the time domain to produce first timedomain equalizer coefficients and second time domain equalizercoefficients, respectively; equalizing the merged information signaltime using the first time domain equalizer coefficients to produceequalized first information signal data symbols; and equalizing themerged information signal time using the first time domain equalizercoefficients to produce equalized second information signal datasymbols.
 2. The method of claim 1, further comprising: despreading theequalized first information signal data symbols; and despreading theequalized second information signal data symbols.
 3. The method of claim1, wherein: the merged information signal comprises a Space TimeTransmit Diversity (STTD) signal; the first information signal datasymbols and the second information signal data symbols carry commondata; and the method further comprises STTD decoding the equalized firstinformation signal data symbols and the equalized second informationsignal data symbols.
 4. The method of claim 1, wherein: the mergedinformation signal comprises a Space Time Transmit Diversity (STTD)signal; the first information signal data symbols and the secondinformation signal data symbols carry common data; and the methodfurther comprises: despreading the equalized first information signaldata symbols; despreading the equalized second information signal datasymbols; and STTD decoding the despread equalized first informationsignal data symbols and the despread equalized second information signaldata symbols.
 5. The method of claim 1, wherein: the merged informationsignal comprises a Multiple Input Multiple Output (MIMO) signal; and thefirst information signal data symbols and the second information signaldata symbols carry differing data.
 6. The method of claim 1, wherein:producing the first information signal frequency domain channel estimateincludes: cluster path processing the first information signal timedomain training symbols; producing the first information signal timedomain channel estimate based upon the cluster path processed firstinformation signal time domain training symbols; and Fast FourierTransforming the first information signal time domain channel estimateto produce the first information signal frequency domain channelestimate; and producing the second information signal frequency domainchannel estimate includes: cluster path processing the secondinformation signal time domain training symbols of the second timedomain signal; producing the second information signal time domainchannel estimate based upon the cluster path processed secondinformation signal time domain training symbols; and Fast FourierTransforming the second information signal time domain channel estimateto produce the second information signal frequency domain channelestimate.
 7. The method of claim 1, wherein: converting the firstfrequency domain equalizer coefficients to the first time domainequalizer coefficients comprises: Inverse Fast Fourier Transforming thefirst frequency domain equalizer coefficients to produce the first timedomain equalizer coefficients; and tap ordering the first time domainequalizer coefficients; and converting the second frequency domainequalizer coefficients to the second time domain equalizer coefficientscomprises: Inverse Fast Fourier Transforming the second frequency domainequalizer coefficients to produce the second time domain equalizercoefficients; and tap ordering the second time domain equalizercoefficients.
 8. The method of claim 1, wherein producing the firstfrequency domain equalizer coefficients and the second frequency domainequalizer coefficients based upon the first frequency domain channelestimate and the second frequency domain channel estimate comprisesperforming a Minimum Mean Squared Error (MMSE) algorithm to produce thefirst frequency domain equalizer coefficients and the second frequencydomain equalizer coefficients.
 9. The method of claim 1, wherein the RFreceiver supports wireless operations selected from the group consistingof cellular wireless communications, wireless metropolitan area networkcommunications, wireless local area network communications, and wirelesspersonal area network communications.
 10. A method for operating a RadioFrequency (RF) receiver comprising: receiving a merged informationsignal that includes a first information signal and a second informationsignal, each of the first and second information signals having timedomain training symbols and data symbols; for each of at least twodiversity paths: processing the first information signal time domaintraining symbols and the second information signal time domain trainingsymbols to produce a first information signal time domain channelestimate and a second information signal time domain channel estimate;converting the first information signal time domain channel estimate andthe second information signal time domain channel estimate to thefrequency domain to produce a first information signal frequency domainchannel estimate and a second information signal frequency domainchannel estimate, respectively; producing first frequency domainequalizer coefficients and second frequency domain equalizercoefficients based upon the first information signal frequency domainchannel estimate and the second information signal frequency domainchannel estimate; converting the first frequency domain equalizercoefficients and the second frequency domain equalizer coefficients tothe time domain to produce first time domain equalizer coefficients andsecond time domain equalizer coefficients, respectively; equalizing themerged information signal time using the first time domain equalizercoefficients to produce equalized first information signal data symbols;and equalizing the merged information signal time using the second timedomain equalizer coefficients to produce equalized second informationsignal data symbols; combining equalized first information signal datasymbols from the at least two diversity paths; and combining equalizedsecond information signal data symbols from the at least two diversitypaths.
 11. The method of claim 10, further comprising: despreading thecombined equalized first information signal data symbols; anddespreading the combined equalized second information signal datasymbols.
 12. The method of claim 10, wherein: the merged informationsignal comprises a Space Time Transmit Diversity (STTD) signal; thefirst information signal data symbols and the second information signaldata symbols carry common data; and the method further comprises STTDdecoding combined equalized first information signal data symbols andcombined equalized second information signal data symbols
 13. The methodof claim 10, wherein: the merged information signal comprises a MultipleInput Multiple Output (MIMO) signal; and the first information signaldata symbols and the second information signal data symbols carrydiffering data.
 14. The method of claim 10, wherein: producing the firstinformation signal frequency domain channel estimate includes: clusterpath processing the first information signal time domain trainingsymbols; producing the first information signal time domain channelestimate based upon the cluster path processed first information signaltime domain training symbols; and Fast Fourier Transforming the firstinformation signal time domain channel estimate to produce the firstinformation signal frequency domain channel estimate; and producing thesecond information signal frequency domain channel estimate includes:cluster path processing the second information signal time domaintraining symbols of the second time domain signal; producing the secondinformation signal time domain channel estimate based upon the clusterpath processed second information signal time domain training symbols;and Fast Fourier Transforming the second information signal time domainchannel estimate to produce the second information signal frequencydomain channel estimate.
 15. The method of claim 10, wherein: convertingthe first frequency domain equalizer coefficients to the first timedomain equalizer coefficients comprises: Inverse Fast FourierTransforming the first frequency domain equalizer coefficients toproduce the first time domain equalizer coefficients; and tap orderingthe first time domain equalizer coefficients; and converting the secondfrequency domain equalizer coefficients to the second time domainequalizer coefficients comprises: Inverse Fast Fourier Transforming thesecond frequency domain equalizer coefficients to produce the secondtime domain equalizer coefficients; and tap ordering the second timedomain equalizer coefficients.
 16. The method of claim 10, whereinproducing first frequency domain equalizer coefficients and secondfrequency domain equalizer coefficients based upon the first frequencydomain channel estimate and the second frequency domain channel estimatecomprises performing a Minimum Mean Squared Error (MMSE) algorithm toproduce the first frequency domain equalizer coefficients and the secondfrequency domain equalizer coefficients.
 17. The method of claim 10,wherein the RF receiver supports wireless operations selected from thegroup consisting of cellular wireless communications, wirelessmetropolitan area network communications, wireless local area networkcommunications, and wireless personal area network communications.
 18. ARadio Frequency (RF) receiver operable upon a merged information signalthat includes a first information signal and a second informationsignal, each of the first and second information signals having timedomain training symbols and data symbols, the RF receiver comprising: aRF front end; and a baseband processing module coupled to the RF frontend and comprising: at least one channel estimator operable to processthe first information signal time domain training symbols and the secondinformation signal time domain training symbols to produce a firstinformation signal time domain channel estimate and a second informationsignal time domain channel estimate; at least one Fast FourierTransformer operable to transform the first information signal timedomain channel estimate and the second information signal time domainchannel estimate to the frequency domain to produce a first informationsignal frequency domain channel estimate and a second information signalfrequency domain channel estimate, respectively; a weight calculatoroperable to produce first frequency domain equalizer coefficients andsecond frequency domain equalizer coefficients based upon the firstinformation signal frequency domain channel estimate and the secondinformation signal frequency domain channel estimate; at least oneInverse Fast Fourier Transformer operable to transform the firstfrequency domain equalizer coefficients and the second frequency domainequalizer coefficients to the time domain to produce first time domainequalizer coefficients and second time domain equalizer coefficients,respectively; and at least one equalizer operable to equalize the mergedinformation signal time using the first time domain equalizercoefficients to produce equalized first information signal data symbolsand to equalize the merged information signal time using the first timedomain equalizer coefficients to produce equalized second informationsignal data symbols.
 19. The RF receiver of claim 18: wherein the mergedinformation signal comprises a Space Time Transmit Diversity (STTD)signal; and further comprising an STTD decoder operable to STTD decodethe equalized first information signal data symbols with the equalizedsecond information signal data symbols.
 20. The RF receiver of claim 18,wherein in producing the first frequency domain equalizer coefficientsand the second frequency domain equalizer coefficients based upon thefirst information signal frequency domain channel estimate and thesecond information signal frequency domain channel estimate, thebaseband processing module is operable to perform a Minimum Mean SquaredError (MMSE) algorithm to produce the frequency domain equalizercoefficients.
 21. The RF receiver of claim 18, wherein the RF front endand the baseband processing module support wireless operations selectedfrom the group consisting of cellular wireless communications, wirelessmetropolitan area network communications, wireless local area networkcommunications, and wireless personal area network communications.
 22. ARadio Frequency (RF) receiver operable upon first and second mergedinformation signals, each including a first information signal and asecond information signal, each of the first and second informationsignals having time domain training symbols and data symbols, the RFreceiver comprising: a RF front end; and a baseband processing modulecoupled to the RF front end comprising: a first diversity path operableto: produce a first information signal time domain channel estimate fromthe first merged information signal and convert the first informationsignal time domain channel estimate to the frequency domain to produce afirst information signal frequency domain channel estimate; and producea second information signal time domain channel estimate from the firstmerged information signal and convert the second information signal timedomain channel estimate to the frequency domain to produce a secondinformation signal frequency domain channel estimate; a second diversitypath operable to: produce a first information signal time domain channelestimate from the second merged information signal and convert the firstinformation signal time domain channel estimate to the frequency domainto produce a first information signal frequency domain channel estimate;and produce a second information signal time domain channel estimatefrom the second merged information signal and convert the secondinformation signal time domain channel estimate to the frequency domainto produce a second information signal frequency domain channelestimate; an equalizer weight calculation module operable to producefirst frequency domain equalizer coefficients, second frequency domainequalizer coefficients, third frequency domain equalizer coefficients,and fourth frequency domain equalizer coefficients based upon the firstinformation signal frequency domain channel estimate of the firstdiversity path, the second information signal frequency domain channelestimate of the first diversity path, the first information signalfrequency domain channel estimate of the second diversity path, thesecond information signal frequency domain channel estimate of thesecond diversity path; the first diversity path further operable to:convert the first frequency domain equalizer coefficients to the timedomain to produce first time domain equalizer coefficients; equalize thefirst merged information signal using the first time domain equalizercoefficients; and equalize the first merged information signal using thesecond time domain equalizer coefficients; the second diversity pathfurther operable to: convert the second frequency domain equalizercoefficients to the time domain to produce second time domain equalizercoefficients; equalize the second merged information signal using thethird time domain equalizer coefficients; and equalize the second mergedinformation signal using the fourth time domain equalizer coefficients.23. The RF receiver of claim 22: wherein the first and second mergedinformation signals comprises Space Time Transmit Diversity (STTD)signals; and further comprising an STTD decoder operable to STTD decodedata symbols produced by the first, second, third, and fourthequalizations.
 24. The RF receiver of claim 22, wherein in producing thefirst, second, third, and fourth frequency domain equalizercoefficients, the baseband processing module is operable to perform aMinimum Mean Squared Error (MMSE) algorithm to produce the frequencydomain equalizer coefficients.
 25. The RF receiver of claim 22, whereinthe RF front end and the baseband processing module support wirelessoperations selected from the group consisting of cellular wirelesscommunications, wireless metropolitan area network communications,wireless local area network communications, and wireless personal areanetwork communications.